Powder cooler



Oct. 11, 1949.

J. BOYCE POWDER COOLER Filed Nov. 5, 1945 INVENTOR:

aomvk BOYCE ATTORNEY Patented Oct. 11, 1949 2,484,070 I POWDER COOLER John Boyce, San Jose, Calif., assignor to Food Machinery and Chemical Corporation, a corporation of Delaware Application November 5, 1945, Serial No. 626,828

2 Claims. (Cl. 259-43) ation to a controlled gas treatment.

It is an object of this invention to produce a novel apparatus by which such an operation may be continuously performed.

In continuous processes, it is not always possible to maintain the flow of material between successive treating units at a uniform rate.

It is another object of this invention to provide an apparatus as aforesaid which will continue to function satisfactorily throughout substantial periods during which the powder handled thereby is fed thereto at an abnormally high rate or taken therefrom at an abnormally low rate.

A further object of the invention is to provide an apparatus as aforesaid in which the powder itself provides seals for the inlet and outlet passages of the apparatus.

While adaptable for performing a wide variety, 7

of continuous operations, the invention will for illustrative purposes, be described herein as when used for continuously cooling egg powder having a relatively low moisture content.

ly through the trough l2 and journalled in bearings Ilia and I1 provided on the trough ends, is a heavy shaft l8 which is adapted to be slowly rotated by a motor l9 which connects with the shaft through a worm and gear mechanism 20. The direction of rotation is indicated by the arrows in Figs. 1, 2 and 3. Provided on the shaft l8 within the trough I2 is a series of powder mixing and progressing paddles which are inclined to cause a longitudinal movement of powder in the trough l2 from the receiving end of the trough to the discharge end thereof, which is to say from the right end to the left end thereof as shown in Fig. 1.

Also fixed on the shaft l 8 at the discharge en of the trough l2 are scoop paddles 26.

The cooler I0 is equipped with a powder delivery mechanism at the receiving end thereof which includes a screw conveyor 3| having a screw 32 rotatably mounted in a screw trough 33 one end of which has a neck 34 which makes The manner of accomplishing the foregoing...

Fig. 3 is a cross-sectional view taken on the,

line 3-3 of Fig. 1.

Fig. 4 is an enlarged detail bottom plan view of the inlet powder valve of the invention.

Referring specifically to the drawings. the powder cooler illustrated therein may be designated generally by the numeral ID. This cooler is mounted on a base H and includes a long powder mixing and cooling trough l2 which has end walls l3 and I4 and acover l5 and is provided with a water jacket l6. Extending longitudinal,-

' hygroscopic powders.

a fluid tight connection with a hole 35 formed in the cooler trough cover l5.

' Secured as by welding to the bottom surface of the cover l5 adjacent the hole 35 is the base 40 of a powder gate 4| Which is hingedly connected to the base by a pin 42 and yieldably held upwardly in the position in which the gate is shown in Fig. 3 by a coil spring 43 (Fig. 4)

Mounted in the cooler trough end i3 is a discharge hopper 50, the upper end of which extends within the space about which the scoop paddles 2B rotate and the lower end of which connects with the receiving end of a cylindrical housing 5| of an elevating screw conveyor 52. Also secured on the end wall I3 are guide walls 53 and 54 which are disposed respectively within and outside of the path traversed by the scoop paddles 26 so as to assist in the delivery of powder engaged by these paddles into the hopper 50.

Operation The cooler in is adapted to be employed in a Wide variety of processes in which it is necessary to give a treatment to a powdered material. In the form in which the inventionis disclosed herein, it is especially adapted for cooling organic In producing powdered eggs with a relatively low moisture content the powder is first formed by spraying the liquid egg into heated air which produces an egg powder with a moisture content of about 5%. To render this relatively unsusceptible to deterioration this powder is redried to reduce the moisture content to below 1%. A process suitable for accomplishing this is disclosed in the co-pending application of W. N. Lindsay and P. C. Wilbur filed herewith. In the redrying of the egg powder in this process, the powder is rendered extremely hygroscopic and is heated to approximately 175 F. To prevent this heat damaging the powder, it is necessary that it be cooled rapidly from this high temperature while excluding :the atmosphere from contact with the. powder. I "1lhe(.:.latter?precaution is necessary because the hygroscopic character of the powder would cause it to rapidly absorb atmospheric moisture if it were exposed to the atmosphere.

The powder cooler lil isradaptedvtozcoolthis. powder after it has been redr-ied inhhelsindsay-t Wilbur process.

The powder cooler It isndesignedito. receive 4 dles 26. These paddles lift portions of the powder engaged thereby upwardly between the guide walls 53 and 54 and deliver these into the open mouth of the hopper Falling into the latter, the powder gravitates into the housing 5| of the screw conveyor '52 and is lifted by the constant rotation of this conveyor to where the powder is sea-led up..=in cans. Y

{hall of the powder from the hopper 50 as this is delivered thereto by the scoop paddles 26. Thus "'arb'o'dy" E0 of powder is maintained in the hopper '50. whioh/ppera'tesras; a, seal closing the discharge iendoof: theccooling chamber 6| to any flow of igasvoreatmosphere. from the conveyor housing 5| this powder, cool it below a temperature of 100" i F., while excluding the atmosphere fromcoi'ltact Q with the powder and while still shielding the powder from the. atmosphere deli-ver .thispowder cupwardly by means. of therscrewr conveyor 52-l-to an epparatusl-by which the powder may;.-be-pa,ckaged: in vacuum onin: anrlatmospherelof an inert jgas-such-asCOz.

Y rBeforei any of this-powden-is fedto the; powder -icoolerl l ,d -the latter is cooled by establishinga-cireso. aslto rcausean orderlydelivery of.,powdered=ma--= terial'to the. cooler lll asdthisis available;-:- and -130 eau-sela-d-isoherge of,powder-.-fr om thetdischarge aendsof the cooleraas will be gmade: clearr.hereinaafter;

" Rotation of. screwrf3 zlcontinuouslyi delivers powder from the: trough: 33 through; the Heck" 34 to-.. thel opening: 35. l-lThe gate 4 I; prevents :this

powder dropping directlyadownwardlyasthrough wthe .=hole-35, but; permits ppowder to she forced downwardly' throughvth-is-holeand past the; gate M1: as. fresh-;powder:-isde1ivered rdownwardly -lrto a-thewzne'ckfi ieby the screw- 32. rThe .spring;-43 ,vholds the. gate 4 l 'upwardlyssoa as r'togmaintain a body of powder tit in the,.neck M-ewhichrseals V irofi =the coolingschambersfil formedflwithinr the .acooler-lfl frornr-theredrier 462 wi-th which-rthe =troughr33.communicateslfreelv e i .aFrom this itrwill be'hoted thatpowdenis;conrtinuously delivered. by; the deliverygmechan-ism waw-ithoutladmitting outside atmosphere-.intor con- .ta'ct with: the; powder -thus. :deliveredror awithout admittingsatmospherefrom; the redrier 62: into ..:the chamber; 6!. I

The spowdemthus;admitted.to=the..ehamber;6l is engaged by the paddles 25 so as to sweep this powder repeatedlyagainst the inner walls of the :cool sinner; surf ace; .ofLthertrough 12-! whereby r :theeheatrin': thist-powder -is;transferred.:to .these .Wvallse and from the latter to? the.;water:ciroulated sinv the: jacket l 6. v :The paddles 25 also thoroughlym-ixthe powder mwhilelthis isin the cooler: lU-sothat when this powder delivered from the cooler it :18. homo geneousquality.

thereby; to progress from-the receiving end of the 1: cooling chamber, 5 I to .the discharge; endwhere it isrdelivered withinathe. path of the scoop padinto the. cooling. chamber 6|.

Fromthe'foregoing it is clear that no opportunityiiis given the powder passing through the chamber 6| of having any contact with the atmosphere or i any other moisture J ,laden a air or gas. :ItbiSmthuS given-mo opportunity-. toeabsorb any moisture while it is being cooled. I It. claim: a r

rlhifn .a powder handling device, the combina- -"tion of E a t trough .disposed substantially horizontally; i a shaft; ,,means, for journalling ;-said rshafti horizontally dn said= trough; ,-lae-seriesoof progressor paddles. ,inounted. on ssaid shaft -wsaid paddlesrbeing, helically angled r means. for; rota-ting said shaftatoecause said; paddles -tmengage powde1:.in saidtroughrto spreadsaid powder-sever t the inner. surface; of; said -.troughf and cause-the powder to progress towards aonerend i-ofssaid trough a hopper; extending-intosaid-trough Jirom -said:end thereof, there being a free space; inzsaid trough encircling saidhopper -ia pair ofrdischarge paddles-. mountedu on saidsshaftldncluding arms located, to. swing inra; plane disposed .inwardly from ,said- :hopper but ,close@ thereto, and blades .mountedpn theends ofcsaid armsand extending "into. said; free space encircling saidsp-hopper so t-thatr-said, blades encircle lsaid-hopperewherr said irom andr vadi acent the 3 path followed ,pyasaid shaft rotates; and a guide wall disposedainwarti-ly blades lto;co operate with eachr-of sagidlbladesgrto support massrof powden-propelled ,upwardlyrby said blade and guide said powder ,intosaid hopper when said-blade moves. out oft-contact withisaid EDI mass, otjwpowden I LAcombination-aain claim- 1,-in which-landm- Ltial pontion of said guide Wallis substantially concentric -.xi itlti said shaft and in: which. a concludportionofi -v said; guide wall. slopes steeply to- Qward rand teminatessatathei adjacent edge :of; said hopper. 1

,liomeoyca REFERENCES ICITED The, following references aare; of record in .the

7 Number I he paddles 25-.alsocause the =powderengaged I UNITED STATES PATENTS 

